1. Field of the Invention
The present invention relates to a method, system, and program for grouping objects.
2. Description of the Related Art
A backup program, such as the International Business Machines Corporation (IBM®) Tivoli® Storage Manager backup program,** maintains an image of the data and programs on systems in a network on a backup storage, such as on tape cartridges. In the event of a system failure or other event that results in a loss of data on the network systems, the backup program may be used to restore the data and programs from the tape cartridges.
Tivoli and Tivoli Storage Manager are trademarks of International Business Machines Corporation. 
In the prior art, the backup client program may define a backup group as specific objects to backup, such as data files, database files, programs, etc. A backup group is a collection of distinct objects, which are managed as a single logical entity to maintain referential consistency in the event that these objects are restored. The objects are grouped because they are related to each other in a meaningful way, such as a set of files that together make up a software application, e.g., a database. Once the backup operation starts, the backup program processes all the received objects specified in the group, writes the received objects to a backup storage medium, and then confirms that the backup of the objects succeeded. If the backup of all objects succeeded, then the backup program will commit the backup. However, if one of the backup objects failed to properly backup, then the entire backup operation would fail, even if the vast majority of the objects successfully backed up. Once the backup has completed, the backup group cannot be modified or altered. Instead, the backup client program would have to create another group, which may be defined with the same objects as in the first group, and then run another backup operation for that new group, which would be maintained separately from the previous backup version.
In the prior art, if files are grouped, then an incremental backup cannot be performed for those data objects in the group that have changed. Instead, the administrator can only schedule full backups of grouped objects to ensure data consistency. Thus, grouped objects can only be backed-up in a single operation. Still further, in prior art backup systems, all the backup objects must originate from the same source system and must be backed up in the same system thread, i.e., only one backup per client per session. Still further, in the prior art, a group cannot be a member of another group, such that groups cannot be nested within one another.
For these reasons, there is a need in the art for improved techniques for grouping objects for use by applications, such as backup programs, that group backup objects.